Sonnet 5's use of sitemap hreflang tags tells search engines which language each page is in and which pages are alternate language versions. This prevents duplicate content penalties (search engines understand EN/ES/FR/DE/PT pages serve different audiences) and enables correct language-serving in search results. It's the proper SEO infrastructure for multilingual sites — and Sonnet 5 implemented it, distinguishing the Compass from simpler multilingual deployments.